LTM4616
SIMPLIFIED BLOCK DIAGRAM
Table 1. Decoupling Requirements. TA = 25°C, Block Diagram Configuration.
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
C
C
External Input Capacitor Requirement
IN1
IN2
(V = 2.7V to 5.5V, V
= 1.5V)
= 2.5V)
I
I
= 8A
= 8A
22
22
µF
µF
IN1
OUT1
OUT2
OUT1
OUT2
(V = 2.7V to 5.5V, V
IN2
C
C
External Output Capacitor Requirement
OUT1
OUT2
(V = 2.7V to 5.5V, V
= 1.5V)
= 2.5V)
I
I
= 8A
= 8A
100
100
µF
µF
IN1
OUT1
OUT2
OUT1
OUT2
(V = 2.7V to 5.5V, V
IN2
OPERATION
Pulling the RUN pins below 1.3V forces the regulators
into a shutdown state, by turning off both MOSFETs. The
TRACK pin is used for programming the output voltage
ramp and voltage tracking during start-up. See the Ap-
plications Information section.
The LTM4616 is a dual-output standalone nonisolated
switching mode DC/DC power supply. It can provide two
8A outputs with few external input and output capacitors.
This module provides precisely regulated output voltages
programmable via external resistors from 0.6V to 5V
DC
DC
over 2.7V to 5.5V input voltages. The typical application
The LTM4616 is internally compensated to be stable over
all operating conditions. Table 3 provides a guideline
for input and output capacitances for several operating
conditions. LTpowerCAD™ design tool is available for fine
tuning transient and stability perfromance. The FB pin is
used to program the output voltage with a single external
resistor to ground.
schematic is shown in Figure 18.
The LTM4616 has integrated constant frequency current
mode regulators and built-in power MOSFET devices with
fast switching speed. The typical switching frequency is
1.5MHz. For switching noise sensitive applications, it can
be externally synchronized from 0.75MHz to 2.25MHz.
Even spread spectrum switching can be implemented in
the design to reduce noise.
Multiphase operation can be easily employed with the
synchronization and phase mode controls. The LTM4616
hasclockinandclockoutforpolyphasingmultipledevices
or frequency synchronization.
With current mode control and internal feedback loop
compensation, the LTM4616 module has sufficient stabil-
ity margins and good transient performance with a wide
range of output capacitors, even with all ceramic output
capacitors.
High efficiency at light loads can be accomplished with
selectableBurstModeoperationusingtheMODEpin.These
light load features will accommodate battery operation.
Efficiency graphs are provided for light load operation in
the Typical Performance Characteristics section.
Currentmodecontrolprovidescycle-by-cyclefastcurrent
limit and thermal shutdown in an overcurrent condition.
Internal overvoltage and undervoltage comparators pull
the open-drain PGOOD output low if the output feedback
voltage exits a 10% window around the regulation point.
The power good pins are disabled during margining.
Output voltage margining is supported, and can be pro-
gramedfrom 5%to 15%usingtheMGNandBSELpins.
4616fe
10
For more information www.linear.com/LTM4616
LINEAR_DIMENSIONS [ Linear Dimensions ]
